HIV Single-Pill Combo Matches PI Regimens

Action Points

Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

Explain that a study found the single-tablet combination of emtricitabine/rilpivirine/tenofovir was as effective as a protease inhibitor-based regimen in maintaining HIV viral load suppression in HIV-infected patients who achieved suppression with the PI-based therapy.

Note that the single-pill regimen reduced total cholesterol, LDL cholesterol, and triglycerides compared with the PI-based regimen.

WASHINGTON – Switching HIV patients from a standard protease inhibitor (PI) regimen to a recently approved single-pill combo led to improvements in lipid measurements, a researcher said here.

The improvements came without a loss of efficacy in suppressing the virus, according to Frank Palella, MD, of Northwestern University Feinberg School of Medicine in Chicago.

The findings come from a 24-week phase III clinical trial, in which researchers randomly assigned patients already on an effective regimen to stay on the same treatment or switch to the single-pill combination of the non-nucleoside reverse transcriptase inhibitor rilpivirine, tenofovir, and emtricitabine, Palella reported at the International AIDS Conference.

Patients were eligible for the trial if they were on a boosted protease inhibitor, combined with two nucleoside reverse transcriptase inhibitors, and had a plasma viral load of less than 50 copies of HIV RNA per milliliter.

The 476 patients either stayed on their regimen or were switched to the combination drug, marketed as Complera.

The primary endpoint, Palella said, was non-inferiority – with a 12% margin -- in the ability of the regimens to keep virus suppressed to below 50 copies per milliliter. Secondary endpoints were lipid changes, safety and tolerability, and changes in the count of CD4-positive T cells.

After 24 weeks, he reported, 93.7% of those on the combination still had suppressed virus, compared with 89.9% of those who did not switch. The difference was within the non-inferiority margin.

Both arms saw a slight increase in the average CD4 count – 20 additional cells per microliter of blood for the combination agent versus 32 for the original regimens – but the difference was not significant.

Those who switched to the combination had lipid improvements that were "significant over every comparison and lipid fraction," Palella said, including average declines of:

25 mg per deciliter in total cholesterol for the combination patients versus 1 in the other arm

16 mg per deciliter versus 0 for LDL cholesterol

53 mg per deciliter for triglycerides versus a gain of 3

0.27 in the total/HDL cholesterol ratio versus a gain of 0.08

All the differences were significant at P<0.001.

Side effects were not markedly different, Palella reported.

When the combination was approved, "there was a lot of expectation that it would be used by people who were switching from other regimens either to simplify therapy or to reduce side effects," commented Joel Gallant, MD, of Johns Hopkins University, who was not part of the study.

The study "shows what you would expect," he told MedPage Today. "People tended to remain suppressed, with some advantages in terms of lipids and also GI tolerability."

Gallant noted that the researchers did not present a breakdown based on which protease inhibitor was in the original regimen, some of which – mainly the older ones – have greater side effects than later drugs.

"I would expect a greater advantage: some older protease inhibitors are less well-tolerated than newer ones, so that the combination might have a greater advantage for people switching from those drugs.

"I would expect more of a difference in tolerability and toxicity if a lot of people were switching from lopinavir/ritonavir (Kaletra) than I would if they were switching from better tolerated PIs," Gallant said.

The study was sponsored by Gilead Sciences. Palella did not report potential conflicts. Several authors are employees of the company.

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